rescript-lang / rescript-lang/rescript

Raising exceptions can generate invalid JavaScript

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Description

The following code:

let x = raise(Not_found)

Compiles to the following JavaScript:

// Generated by ReScript, PLEASE EDIT WITH CARE


throw {
      RE_EXN_ID: "Not_found",
      Error: new Error()
    };

export {
  x ,
}
/* x Not a pure module */

Which exports a variable x that does not exist on the final output.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by compiling the minimal ReScript example in the issue and inspecting the generated JavaScript around the top-level throw and export. Trace the compiler path that handles a raised exception at module scope; done means the generated JavaScript is valid and does not export the nonexistent x variable.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript
Domain
compilers
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
48/100

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